Field of the Invention
This invention relates to an apparatus for the production of a substantially non-turbulent stream of cooling gas for quenching one or more synthetic filaments produced by a melt-spinning process.
In a typical melt-spinning process, one or more filaments is extruded from one or more spinnerettes and passed into a quenching chamber. A diffuser separates the quenching chamber from an adjoining plenum chamber which is in communication with the cooling gas supply system. The synthetic polymer extruding from the spinnerette is a viscous liquid at an elevated temperature. Cooling of this liquid takes place in the quenching chamber where a cooling gas, which is usually air, is contacted with the filaments. The cooling gas enters the quenching chamber from the plenum chamber through the diffuser. The function of the diffuser is to reduce cooling gas turbulence in the quenching chamber where the turbulence can detract from uniformity of the filaments.
Faster yarn speeds coupled with decreased distances between spun filaments to increase yield causes undesirable crowding of the filaments, frequently with interfilament collisions, in the quenching zone. As a consequence, improving the stability of the threadline and improving yarn uniformity are very important. Control of the quench fluid flow rate and more uniform distribution of the quench fluid in the quenching chamber are necessary.
The diffuser has been the primary means of reducing turbulence in the cooling gas stream. There are a variety of diffusers in the prior art; these include screens, porous foam, perforated metal plates, sintered metal, metallic wool, felt and sandwiches of mesh screens. U.S. Pat. Nos. 3,834,847 to Fletcher and 3,619,452 to Harrison, both of which are hereby incorporated by reference, teach use of a porous foam diffuser; the former patent also teaches the layering of foam on a restrictor plate to permit attainment of varying gas distribution patterns in the plenum chamber. Other patents which show use of foam diffusers include U.S. Pat. Nos. 4,285,646 to Waite and 4,332,764 to Brayford et al., both of which are hereby incorporated by reference.
Quench systems which allow different cooling gas rates to be supplied to varying sections of the quenching chamber are also known. See U.S. Pat. Nos. 3,999,910 to Pendlebury et al., 3,274,644 to Massey et al., and 2,273,105 to Heckert, all of which are hereby incorporated by reference. A honeycombed flow rectifier system is shown in U. S. Pat. No. 3,320,343 to Buschmann et al., hereby incorporated by reference.
The present invention has been developed to improve quench fluid penetration of a filament bundle for an increased number of filaments.